UFC star on attempted robbery: 'I knew how to defend myself'

Inundated with messages of support after taking on a wannabe thief, UFC fighter Polyana Viana has begun to reflect on an incident that has gone viral.

The 26-year-old was waiting outside her apartment in Rio de Janeiro when she was approached by a man demanding her phone.

Viana's assailant had a fake gun but he hadn't accounted for the Brazilian's Mixed Martial Arts (MMA) training as she launched a devastating counterattack -- aiming two punches and a kick at the man before subduing him with a choke hold from behind.

"When he got close, I already thought if this guy is a thief, I'll do this and that. I already knew what I was going to do," Viana told CNN Sport.

UFC star Polyana Viana has used her fighting skills to apprehend an alleged thief. (CNN)

"I did not do it on impulse, I was calm, I knew what I was going to do. But I only did it because I knew he did not have a gun."

Viana held the man down until police arrived to make the arrest.

Pictures from the alleged incident, reportedly taken by Viana, appeared on UFC president Dana White's Instagram account showing the man's gruesome injuries.

"On the left is @polyanaviana, one of our @UFC fighters and on the right is the guy who tried to rob her," wrote White, who added: "#Badf***ingidea"

Meanwhile, Viana hasn't been able to answer all the messages of support she's received.

"I got to see how much people like me," said the Brazilian, who has a 1-1 record in UFC.

Polyana Viana says 'I only did it because I knew he did not have a gun'. (AAP)

"My fans, family, friends, they all sent me messages asking me if I am OK or if I got hurt. I still haven't answered every one."

The Rio police department were unable to confirm the individuals involved in the incident but told CNN Sport that an attempted robbery had taken place.

"A criminal was found immobilized by civilians after trying to rob a person on site," a statement read. "A fake gun was seized with him."

Viana says "nothing had changed" following her ordeal and that's she been busy training -- and dealing with the influx of attention.

But Viana cautioned she doesn't want her actions to inspire others who might find themselves in a similar situation.

"I would not recommend it at all. I'm a trained fighter. I knew how to defend myself because I have knowledge and more so because I managed to stay calm," she added.